[1][2] Born in London, Forster was the godchild (and son) of Leonard Llewelyn Bulkeley Williams.
Forster studied at Marlborough College, Trinity Hall, Cambridge, where he read Modern Languages (a contemporary of Donald MacLean) and from where he obtained his BA in 1934 and MA in 1938, and the University of Basel, where he was awarded a PhD in 1938.
[2] During World War II he worked as an intelligence assessor/translator at Bletchley Park, with the rank of Lieutenant commander of the Royal Naval Reserve.
[1][2] He was also the President of the International Association for German Studies (Internationale Vereinigung für Germanistik, IVG) from 1970 to 1975.
[1] He was for many years editor of German Life and Letters, whose most famous subscriber is perhaps John le Carré's character George Smiley.